The EMG signal represents an electrical signal associated with an activity of a skeletal muscular fiber and has been used to control a prosthesis or to develop a human computer interface (HCI) technology.
In order to control the prosthesis to develop an EMG based HCI technology, a sensor to detect the EMG signal must be attached around a portion, e.g., an arm, of a body. Since the inaccurate location of the EMG electrode results in a malfunction of the prosthesis or the HCI due to a noise of the body itself, the location of the EMG electrode must be precisely detected depending on the motion of the body, e.g., a bending of an arm.
Accordingly, an examiner, e.g., an anatomist is required to detect the location of the EMG electrode depending on the motion of the body. Since the prosthesis or the HCI apparatus must be occasionally attached or detached as necessity requires, it is difficult for the examinee himself/herself to detect the location of the EMG electrode.
In order to overcome such difficulty, an instant power of the EMG electrode to be detected is displayed on an light emitting diode (LED) so that the level of the LED may be used to determine the location of the EMG electrode. Accordingly, the location of the EMG electrode was directly measured by the eyes or directly marked with a pen on the skin of the examinee.
Since, however, an EMG sensor is usually attached around one arm of the examinee, it is more difficult for the examinee to determine the location of the EMG electrode and to mark same with a pen taken in the hand of the other arm of the examinee on which no EMG sensor is attached. Further, if a frequency modulation procedure is used to determine the fatigue rate of the muscle or the abnormal condition of the muscle, an additional apparatus such as a frequency analyzer must be required.